京津冀平原区冬季大气环境容量变化:观测与预估OACSTPCD

Based on ERA5 reanalysis data,the spatiotemporal variation characteristics and related influencing factors of Atmosphere Environmental Capacity(AEC)in winter over the Beijing-Tianjin-Hebei(BTH)region were explored.Results show that the winter AEC over the BTH region exhibits a distribution pattern of low in the southwest and high in the north,with low values concentrates in the plain areas.The changes of AEC over the BTH Plain are closely related to the East Asian winter monsoon,boundary layer height,average wind speed within the boundary layer,and ventilation intensity.The strong East Asian winter monsoon,high boundary layer height,high average wind speed within the boundary layer,and strong ventilation intensity result in higher AEC,and vice versa.Further more,the regional climate model RegCM4 was used to simulate the dynamic downscaling of three CMIP5 global climate models,and the changes in winter AEC over the BTH plain region under RCP4.5 and RCP8.5 scenarios were estimated.The projections indicate that compared with the period of 1986 to 2005,the winter AEC over the BTH plain region will decrease in both the middle and late 21st century under two scenarios,with a higher decrease in the late 21st century than the middle period and a greater change in the RCP8.5 scenario than in the RCP4.5 scenario.The above changes are related to the weakening of the East Asian winter monsoon,the northward movement of the East Asian westerly jet,the decrease in boundary layer height,and the decrease in average wind speed within the boundary layer.